Reader Question: Effect of Temp on EV Battery Charge?

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Here’s the latest reader question, along with my reply! 

Jeremy asks: I know that cold temperatures cause an EV’s range to plummet, even if not using the heater. My question is whether a battery will take a full charge in cold weather. What I’m curious about is whether the available KWh after a full charge will increase when it gets warm. In other words, does cold weather limit the charge capacity of the battery. I’ve searched for an answer but can only find info on range loss, not battery capacity.

My reply: My understanding is that most EVs have a thermal management system – including a battery heater as well as a battery cooling system – to maintain the battery pack’s temperature within a range such that it isn’t damaged by excessive heat or unable to be recharged due to excessive cold. They are also “managed” to accept charge at a certain rate – to avoid damage (and fire- hopefully). This is why EV battery packs don’t fully recharge at “fast” chargers in the time advertised.

So, assuming the EV does have a thermal management system, I would expect that it can take the same charge regardless of ambient temp but that the degree of warm or cold outside will affect the rate at which the available charge is depleted.

If it’s very cold out, the EV will be running its heater – even as you charge – so it will be discharging even before you begin driving. If it’s very hot out, then the system would be working to keep the battery pack cool – also drawing electricity.

This is just another of the serial problems with EVs for which there is no IC analog. It’s 17 degrees here in the Woods of SW Virginia today and the Ford Escape press car I have sitting in my driveway isn’t much if at all affected by this. It may take a couple of minutes longer to warm up, but there’s very little “energy penalty” to pay due to to the cold and no range penalty to pay for running the heater at full tilt because – as you know – in an IC car, the heat is basically free, energy-wise. The cabin is warmed by the cast-off heat of the running engine.

Even using the AC when it’s very hot out has little effect on an IC car’s range whereas using the AC in an electric car does.

And, of course, even if using the heat and AC reduced an IC car’s range by 25 percent it wouldn’t matter much in practical terms because the IC car can be refueled easily and quickly whereas the EV…

Sigh. And they ask me why I drink!

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3 COMMENTS

  1. There is a reason why internal combustion won over electric a hundred years ago. It really is quite simple, IC works and electric doesn’t.

    In spite of the billions basically wasted on research in the last decade, that reality hasn’t changed.

    Even though the electric fanboys have blamed the oil and car industry for electric never taking off, it’s the electric vehicle itself that is to blame.

    At the place I work there is an electric golf cart. Though it was parked in a heated garage, was fully charged, it wouldn’t work after being outside in the 30 degree weather after a half hour or so. Just wouldn’t operate after it was in the “cold” for not that long. It doesn’t have heater for the battery, so we knew the range would fall off, but down to nothing? We didn’t think it’s a summer only vehicle but it is.

  2. Speaking of EV temp issues, Antonio Felix DaCosta lost the Formula E race in Santiago, Chile due to thermal management issues. Because FE races in Santiago in January or February, it’s the peak of summer time down there; think of July or August up here. Anyway, temps are 90 better on race day, so the battery temps ALWAYS play a role in the FE race there-always! DaCosta had a winning car and had just made a pass for the lead; unfortunately, his batteries were running hot, so his engineers told him to back off and bring the car home. BMW’s Max Guenther went on for the win. For the Santiago race, the winner is more often than not the one who best manages the battery temps.

    While ICE open wheel race cars (e.g. F1 or IndyCar) can experience cooling issues, it’s only if they sit for a prolonged pit stop (no air flow through the radiators), or if they get piece of debris caught in the radiator. Those exceptions aside, an ICE open wheel race car won’t have cooling issues. As long as they’re moving, they’ll be all right. The teams will have already figured out how much cooling is needed for race day, so that won’t be an issue.

  3. It seems most people, ok, nearly every person you speak with about EV’s have no idea they have a liquid cooling/heating system just for the battery. I’ve seen an almost brand new Tesla have a leak in the system and according to the shop owner, it’s a real bitch to fix due to all the panels you have to remove that are held on with a sealant similar to RTV, the really difficult stuff to remove.

    Nothing to wear out on an EV couldn’t be further from the truth. They often have worn out axles and steering and motor problems. The panels are often aligned (Tesla)poorly causing water to build up between them. It makes the doors especially prone to freezing and being stuck. The fix on them is very expensive too and takes a lot of labor and often replacement of the panel or panels involved.

    A lot of people who don’t live in southern California are finding out the hard way and are rapidly becoming an ex-Tesla fanboi.

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